drivers/video/vfb.c

   1 /*
   2  *  linux/drivers/video/vfb.c -- Virtual frame buffer device
   3  *
   4  *      Copyright (C) 2002 James Simmons
   5  *
   6  *      Copyright (C) 1997 Geert Uytterhoeven
   7  *
   8  *  This file is subject to the terms and conditions of the GNU General Public
   9  *  License. See the file COPYING in the main directory of this archive for
  10  *  more details.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/kernel.h>
  15 #include <linux/errno.h>
  16 #include <linux/string.h>
  17 #include <linux/mm.h>
  18 #include <linux/slab.h>
  19 #include <linux/vmalloc.h>
  20 #include <linux/delay.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/platform_device.h>
  23
  24 #include <linux/fb.h>
  25 #include <linux/init.h>
  26
  27     /*
  28      *  RAM we reserve for the frame buffer. This defines the maximum screen
  29      *  size
  30      *
  31      *  The default can be overridden if the driver is compiled as a module
  32      */
  33
  34 #define VIDEOMEMSIZE    (1*1024*1024)   /* 1 MB */
  35
  36 static void *videomemory;
  37 static u_long videomemorysize = VIDEOMEMSIZE;
  38 module_param(videomemorysize, ulong, 0);
  39
  40 /**********************************************************************
  41  *
  42  * Memory management
  43  *
  44  **********************************************************************/
  45 static void *rvmalloc(unsigned long size)
  46 {
  47         void *mem;
  48         unsigned long adr;
  49
  50         size = PAGE_ALIGN(size);
  51         mem = vmalloc_32(size);
  52         if (!mem)
  53                 return NULL;
  54
  55         memset(mem, 0, size); /* Clear the ram out, no junk to the user */
  56         adr = (unsigned long) mem;
  57         while (size > 0) {
  58                 SetPageReserved(vmalloc_to_page((void *)adr));
  59                 adr += PAGE_SIZE;
  60                 size -= PAGE_SIZE;
  61         }
  62
  63         return mem;
  64 }
  65
  66 static void rvfree(void *mem, unsigned long size)
  67 {
  68         unsigned long adr;
  69
  70         if (!mem)
  71                 return;
  72
  73         adr = (unsigned long) mem;
  74         while ((long) size > 0) {
  75                 ClearPageReserved(vmalloc_to_page((void *)adr));
  76                 adr += PAGE_SIZE;
  77                 size -= PAGE_SIZE;
  78         }
  79         vfree(mem);
  80 }
  81
  82 static struct fb_var_screeninfo vfb_default __initdata = {
  83         .xres =         640,
  84         .yres =         480,
  85         .xres_virtual = 640,
  86         .yres_virtual = 480,
  87         .bits_per_pixel = 8,
  88         .red =          { 0, 8, 0 },
  89         .green =        { 0, 8, 0 },
  90         .blue =         { 0, 8, 0 },
  91         .activate =     FB_ACTIVATE_TEST,
  92         .height =       -1,
  93         .width =        -1,
  94         .pixclock =     20000,
  95         .left_margin =  64,
  96         .right_margin = 64,
  97         .upper_margin = 32,
  98         .lower_margin = 32,
  99         .hsync_len =    64,
 100         .vsync_len =    2,
 101         .vmode =        FB_VMODE_NONINTERLACED,
 102 };
 103
 104 static struct fb_fix_screeninfo vfb_fix __initdata = {
 105         .id =           "Virtual FB",
 106         .type =         FB_TYPE_PACKED_PIXELS,
 107         .visual =       FB_VISUAL_PSEUDOCOLOR,
 108         .xpanstep =     1,
 109         .ypanstep =     1,
 110         .ywrapstep =    1,
 111         .accel =        FB_ACCEL_NONE,
 112 };
 113
 114 static int vfb_enable __initdata = 0;   /* disabled by default */
 115 module_param(vfb_enable, bool, 0);
 116
 117 static int vfb_check_var(struct fb_var_screeninfo *var,
 118                          struct fb_info *info);
 119 static int vfb_set_par(struct fb_info *info);
 120 static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
 121                          u_int transp, struct fb_info *info);
 122 static int vfb_pan_display(struct fb_var_screeninfo *var,
 123                            struct fb_info *info);
 124 static int vfb_mmap(struct fb_info *info,
 125                     struct vm_area_struct *vma);
 126
 127 static struct fb_ops vfb_ops = {
 128         .fb_read        = fb_sys_read,
 129         .fb_write       = fb_sys_write,
 130         .fb_check_var   = vfb_check_var,
 131         .fb_set_par     = vfb_set_par,
 132         .fb_setcolreg   = vfb_setcolreg,
 133         .fb_pan_display = vfb_pan_display,
 134         .fb_fillrect    = sys_fillrect,
 135         .fb_copyarea    = sys_copyarea,
 136         .fb_imageblit   = sys_imageblit,
 137         .fb_mmap        = vfb_mmap,
 138 };
 139
 140     /*
 141      *  Internal routines
 142      */
 143
 144 static u_long get_line_length(int xres_virtual, int bpp)
 145 {
 146         u_long length;
 147
 148         length = xres_virtual * bpp;
 149         length = (length + 31) & ~31;
 150         length >>= 3;
 151         return (length);
 152 }
 153
 154     /*
 155      *  Setting the video mode has been split into two parts.
 156      *  First part, xxxfb_check_var, must not write anything
 157      *  to hardware, it should only verify and adjust var.
 158      *  This means it doesn't alter par but it does use hardware
 159      *  data from it to check this var.
 160      */
 161
 162 static int vfb_check_var(struct fb_var_screeninfo *var,
 163                          struct fb_info *info)
 164 {
 165         u_long line_length;
 166
 167         /*
 168          *  FB_VMODE_CONUPDATE and FB_VMODE_SMOOTH_XPAN are equal!
 169          *  as FB_VMODE_SMOOTH_XPAN is only used internally
 170          */
 171
 172         if (var->vmode & FB_VMODE_CONUPDATE) {
 173                 var->vmode |= FB_VMODE_YWRAP;
 174                 var->xoffset = info->var.xoffset;
 175                 var->yoffset = info->var.yoffset;
 176         }
 177
 178         /*
 179          *  Some very basic checks
 180          */
 181         if (!var->xres)
 182                 var->xres = 1;
 183         if (!var->yres)
 184                 var->yres = 1;
 185         if (var->xres > var->xres_virtual)
 186                 var->xres_virtual = var->xres;
 187         if (var->yres > var->yres_virtual)
 188                 var->yres_virtual = var->yres;
 189         if (var->bits_per_pixel <= 1)
 190                 var->bits_per_pixel = 1;
 191         else if (var->bits_per_pixel <= 8)
 192                 var->bits_per_pixel = 8;
 193         else if (var->bits_per_pixel <= 16)
 194                 var->bits_per_pixel = 16;
 195         else if (var->bits_per_pixel <= 24)
 196                 var->bits_per_pixel = 24;
 197         else if (var->bits_per_pixel <= 32)
 198                 var->bits_per_pixel = 32;
 199         else
 200                 return -EINVAL;
 201
 202         if (var->xres_virtual < var->xoffset + var->xres)
 203                 var->xres_virtual = var->xoffset + var->xres;
 204         if (var->yres_virtual < var->yoffset + var->yres)
 205                 var->yres_virtual = var->yoffset + var->yres;
 206
 207         /*
 208          *  Memory limit
 209          */
 210         line_length =
 211             get_line_length(var->xres_virtual, var->bits_per_pixel);
 212         if (line_length * var->yres_virtual > videomemorysize)
 213                 return -ENOMEM;
 214
 215         /*
 216          * Now that we checked it we alter var. The reason being is that the video
 217          * mode passed in might not work but slight changes to it might make it
 218          * work. This way we let the user know what is acceptable.
 219          */
 220         switch (var->bits_per_pixel) {
 221         case 1:
 222         case 8:
 223                 var->red.offset = 0;
 224                 var->red.length = 8;
 225                 var->green.offset = 0;
 226                 var->green.length = 8;
 227                 var->blue.offset = 0;
 228                 var->blue.length = 8;
 229                 var->transp.offset = 0;
 230                 var->transp.length = 0;
 231                 break;
 232         case 16:                /* RGBA 5551 */
 233                 if (var->transp.length) {
 234                         var->red.offset = 0;
 235                         var->red.length = 5;
 236                         var->green.offset = 5;
 237                         var->green.length = 5;
 238                         var->blue.offset = 10;
 239                         var->blue.length = 5;
 240                         var->transp.offset = 15;
 241                         var->transp.length = 1;
 242                 } else {        /* RGB 565 */
 243                         var->red.offset = 0;
 244                         var->red.length = 5;
 245                         var->green.offset = 5;
 246                         var->green.length = 6;
 247                         var->blue.offset = 11;
 248                         var->blue.length = 5;
 249                         var->transp.offset = 0;
 250                         var->transp.length = 0;
 251                 }
 252                 break;
 253         case 24:                /* RGB 888 */
 254                 var->red.offset = 0;
 255                 var->red.length = 8;
 256                 var->green.offset = 8;
 257                 var->green.length = 8;
 258                 var->blue.offset = 16;
 259                 var->blue.length = 8;
 260                 var->transp.offset = 0;
 261                 var->transp.length = 0;
 262                 break;
 263         case 32:                /* RGBA 8888 */
 264                 var->red.offset = 0;
 265                 var->red.length = 8;
 266                 var->green.offset = 8;
 267                 var->green.length = 8;
 268                 var->blue.offset = 16;
 269                 var->blue.length = 8;
 270                 var->transp.offset = 24;
 271                 var->transp.length = 8;
 272                 break;
 273         }
 274         var->red.msb_right = 0;
 275         var->green.msb_right = 0;
 276         var->blue.msb_right = 0;
 277         var->transp.msb_right = 0;
 278
 279         return 0;
 280 }
 281
 282 /* This routine actually sets the video mode. It's in here where we
 283  * the hardware state info->par and fix which can be affected by the
 284  * change in par. For this driver it doesn't do much.
 285  */
 286 static int vfb_set_par(struct fb_info *info)
 287 {
 288         info->fix.line_length = get_line_length(info->var.xres_virtual,
 289                                                 info->var.bits_per_pixel);
 290         return 0;
 291 }
 292
 293     /*
 294      *  Set a single color register. The values supplied are already
 295      *  rounded down to the hardware's capabilities (according to the
 296      *  entries in the var structure). Return != 0 for invalid regno.
 297      */
 298
 299 static int vfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
 300                          u_int transp, struct fb_info *info)
 301 {
 302         if (regno >= 256)       /* no. of hw registers */
 303                 return 1;
 304         /*
 305          * Program hardware... do anything you want with transp
 306          */
 307
 308         /* grayscale works only partially under directcolor */
 309         if (info->var.grayscale) {
 310                 /* grayscale = 0.30*R + 0.59*G + 0.11*B */
 311                 red = green = blue =
 312                     (red * 77 + green * 151 + blue * 28) >> 8;
 313         }
 314
 315         /* Directcolor:
 316          *   var->{color}.offset contains start of bitfield
 317          *   var->{color}.length contains length of bitfield
 318          *   {hardwarespecific} contains width of RAMDAC
 319          *   cmap[X] is programmed to (X << red.offset) | (X << green.offset) | (X << blue.offset)
 320          *   RAMDAC[X] is programmed to (red, green, blue)
 321          *
 322          * Pseudocolor:
 323          *    uses offset = 0 && length = RAMDAC register width.
 324          *    var->{color}.offset is 0
 325          *    var->{color}.length contains widht of DAC
 326          *    cmap is not used
 327          *    RAMDAC[X] is programmed to (red, green, blue)
 328          * Truecolor:
 329          *    does not use DAC. Usually 3 are present.
 330          *    var->{color}.offset contains start of bitfield
 331          *    var->{color}.length contains length of bitfield
 332          *    cmap is programmed to (red << red.offset) | (green << green.offset) |
 333          *                      (blue << blue.offset) | (transp << transp.offset)
 334          *    RAMDAC does not exist
 335          */
 336 #define CNVT_TOHW(val,width) ((((val)<<(width))+0x7FFF-(val))>>16)
 337         switch (info->fix.visual) {
 338         case FB_VISUAL_TRUECOLOR:
 339         case FB_VISUAL_PSEUDOCOLOR:
 340                 red = CNVT_TOHW(red, info->var.red.length);
 341                 green = CNVT_TOHW(green, info->var.green.length);
 342                 blue = CNVT_TOHW(blue, info->var.blue.length);
 343                 transp = CNVT_TOHW(transp, info->var.transp.length);
 344                 break;
 345         case FB_VISUAL_DIRECTCOLOR:
 346                 red = CNVT_TOHW(red, 8);        /* expect 8 bit DAC */
 347                 green = CNVT_TOHW(green, 8);
 348                 blue = CNVT_TOHW(blue, 8);
 349                 /* hey, there is bug in transp handling... */
 350                 transp = CNVT_TOHW(transp, 8);
 351                 break;
 352         }
 353 #undef CNVT_TOHW
 354         /* Truecolor has hardware independent palette */
 355         if (info->fix.visual == FB_VISUAL_TRUECOLOR) {
 356                 u32 v;
 357
 358                 if (regno >= 16)
 359                         return 1;
 360
 361                 v = (red << info->var.red.offset) |
 362                     (green << info->var.green.offset) |
 363                     (blue << info->var.blue.offset) |
 364                     (transp << info->var.transp.offset);
 365                 switch (info->var.bits_per_pixel) {
 366                 case 8:
 367                         break;
 368                 case 16:
 369                         ((u32 *) (info->pseudo_palette))[regno] = v;
 370                         break;
 371                 case 24:
 372                 case 32:
 373                         ((u32 *) (info->pseudo_palette))[regno] = v;
 374                         break;
 375                 }
 376                 return 0;
 377         }
 378         return 0;
 379 }
 380
 381     /*
 382      *  Pan or Wrap the Display
 383      *
 384      *  This call looks only at xoffset, yoffset and the FB_VMODE_YWRAP flag
 385      */
 386
 387 static int vfb_pan_display(struct fb_var_screeninfo *var,
 388                            struct fb_info *info)
 389 {
 390         if (var->vmode & FB_VMODE_YWRAP) {
 391                 if (var->yoffset < 0
 392                     || var->yoffset >= info->var.yres_virtual
 393                     || var->xoffset)
 394                         return -EINVAL;
 395         } else {
 396                 if (var->xoffset + var->xres > info->var.xres_virtual ||
 397                     var->yoffset + var->yres > info->var.yres_virtual)
 398                         return -EINVAL;
 399         }
 400         info->var.xoffset = var->xoffset;
 401         info->var.yoffset = var->yoffset;
 402         if (var->vmode & FB_VMODE_YWRAP)
 403                 info->var.vmode |= FB_VMODE_YWRAP;
 404         else
 405                 info->var.vmode &= ~FB_VMODE_YWRAP;
 406         return 0;
 407 }
 408
 409     /*
 410      *  Most drivers don't need their own mmap function
 411      */
 412
 413 static int vfb_mmap(struct fb_info *info,
 414                     struct vm_area_struct *vma)
 415 {
 416         unsigned long start = vma->vm_start;
 417         unsigned long size = vma->vm_end - vma->vm_start;
 418         unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
 419         unsigned long page, pos;
 420
 421         if (offset + size > info->fix.smem_len) {
 422                 return -EINVAL;
 423         }
 424
 425         pos = (unsigned long)info->fix.smem_start + offset;
 426
 427         while (size > 0) {
 428                 page = vmalloc_to_pfn((void *)pos);
 429                 if (remap_pfn_range(vma, start, page, PAGE_SIZE, PAGE_SHARED)) {
 430                         return -EAGAIN;
 431                 }
 432                 start += PAGE_SIZE;
 433                 pos += PAGE_SIZE;
 434                 if (size > PAGE_SIZE)
 435                         size -= PAGE_SIZE;
 436                 else
 437                         size = 0;
 438         }
 439
 440         vma->vm_flags |= VM_RESERVED;   /* avoid to swap out this VMA */
 441         return 0;
 442
 443 }
 444
 445 #ifndef MODULE
 446 /*
 447  * The virtual framebuffer driver is only enabled if explicitly
 448  * requested by passing 'video=vfb:' (or any actual options).
 449  */
 450 static int __init vfb_setup(char *options)
 451 {
 452         char *this_opt;
 453
 454         vfb_enable = 0;
 455
 456         if (!options)
 457                 return 1;
 458
 459         vfb_enable = 1;
 460
 461         if (!*options)
 462                 return 1;
 463
 464         while ((this_opt = strsep(&options, ",")) != NULL) {
 465                 if (!*this_opt)
 466                         continue;
 467                 /* Test disable for backwards compatibility */
 468                 if (!strcmp(this_opt, "disable"))
 469                         vfb_enable = 0;
 470         }
 471         return 1;
 472 }
 473 #endif  /*  MODULE  */
 474
 475     /*
 476      *  Initialisation
 477      */
 478
 479 static int __init vfb_probe(struct platform_device *dev)
 480 {
 481         struct fb_info *info;
 482         int retval = -ENOMEM;
 483
 484         /*
 485          * For real video cards we use ioremap.
 486          */
 487         if (!(videomemory = rvmalloc(videomemorysize)))
 488                 return retval;
 489
 490         /*
 491          * VFB must clear memory to prevent kernel info
 492          * leakage into userspace
 493          * VGA-based drivers MUST NOT clear memory if
 494          * they want to be able to take over vgacon
 495          */
 496         memset(videomemory, 0, videomemorysize);
 497
 498         info = framebuffer_alloc(sizeof(u32) * 256, &dev->dev);
 499         if (!info)
 500                 goto err;
 501
 502         info->screen_base = (char __iomem *)videomemory;
 503         info->fbops = &vfb_ops;
 504
 505         retval = fb_find_mode(&info->var, info, NULL,
 506                               NULL, 0, NULL, 8);
 507
 508         if (!retval || (retval == 4))
 509                 info->var = vfb_default;
 510         vfb_fix.smem_start = (unsigned long) videomemory;
 511         vfb_fix.smem_len = videomemorysize;
 512         info->fix = vfb_fix;
 513         info->pseudo_palette = info->par;
 514         info->par = NULL;
 515         info->flags = FBINFO_FLAG_DEFAULT;
 516
 517         retval = fb_alloc_cmap(&info->cmap, 256, 0);
 518         if (retval < 0)
 519                 goto err1;
 520
 521         retval = register_framebuffer(info);
 522         if (retval < 0)
 523                 goto err2;
 524         platform_set_drvdata(dev, info);
 525
 526         printk(KERN_INFO
 527                "fb%d: Virtual frame buffer device, using %ldK of video memory\n",
 528                info->node, videomemorysize >> 10);
 529         return 0;
 530 err2:
 531         fb_dealloc_cmap(&info->cmap);
 532 err1:
 533         framebuffer_release(info);
 534 err:
 535         rvfree(videomemory, videomemorysize);
 536         return retval;
 537 }
 538
 539 static int vfb_remove(struct platform_device *dev)
 540 {
 541         struct fb_info *info = platform_get_drvdata(dev);
 542
 543         if (info) {
 544                 unregister_framebuffer(info);
 545                 rvfree(videomemory, videomemorysize);
 546                 fb_dealloc_cmap(&info->cmap);
 547                 framebuffer_release(info);
 548         }
 549         return 0;
 550 }
 551
 552 static struct platform_driver vfb_driver = {
 553         .probe  = vfb_probe,
 554         .remove = vfb_remove,
 555         .driver = {
 556                 .name   = "vfb",
 557         },
 558 };
 559
 560 static struct platform_device *vfb_device;
 561
 562 static int __init vfb_init(void)
 563 {
 564         int ret = 0;
 565
 566 #ifndef MODULE
 567         char *option = NULL;
 568
 569         if (fb_get_options("vfb", &option))
 570                 return -ENODEV;
 571         vfb_setup(option);
 572 #endif
 573
 574         if (!vfb_enable)
 575                 return -ENXIO;
 576
 577         ret = platform_driver_register(&vfb_driver);
 578
 579         if (!ret) {
 580                 vfb_device = platform_device_alloc("vfb", 0);
 581
 582                 if (vfb_device)
 583                         ret = platform_device_add(vfb_device);
 584                 else
 585                         ret = -ENOMEM;
 586
 587                 if (ret) {
 588                         platform_device_put(vfb_device);
 589                         platform_driver_unregister(&vfb_driver);
 590                 }
 591         }
 592
 593         return ret;
 594 }
 595
 596 module_init(vfb_init);
 597
 598 #ifdef MODULE
 599 static void __exit vfb_exit(void)
 600 {
 601         platform_device_unregister(vfb_device);
 602         platform_driver_unregister(&vfb_driver);
 603 }
 604
 605 module_exit(vfb_exit);
 606
 607 MODULE_LICENSE("GPL");
 608 #endif                          /* MODULE */